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Verified Technologies for SmartWay and Clean Diesel

Clean Diesel Technologies, Inc. – Purifilter Plus M DPF

This retrofit technology is included on EPA's Verified Technologies List for Clean Diesel.

On this page:

Technology specifications

Engine Model/Application

Highway, light, medium, and heavy heavy-duty EGR and non-EGR engines; not originally certified or equipped with DPF, originally manufactured from 1994-2010, listed in Table A 

Retrofit Fuel, Max Sulfur

15 parts per million (ppm)

Reduction in particulate matter (PM)1


Reduction in nitrogen oxide (NOx)1


Reduction in hydrocarbons (HC)1

0% (for DOC equipped engines)
or 70% (for non-DOC equipped engines)

Reduction in carbon monoxide (CO)1 75%

1 Baseline assumes an unmodified engine running on fuel with 15 ppm sulfur or less.

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Criteria to achieve emission reductions

This technology is approved for use on the engines and/or vehicles detailed in the enclosure provided all of the operating criteria are met as described below:

  1. As there may be variations from application to application, data logging and a review of actual vehicle operating conditions is required to ensure Purifilter Plus M compatibility. The installer must provide the fleet owners and/or operators with a copy of the pre- and post-installation checklists, as well as copies of the data logging results and recommended regeneration schedules. Fleet owners/operators are responsible for adhering to the recommended regeneration schedule. At a minimum, CDTi recommends that all fleets proactively regenerate the Purifilter Plus M every 4 to 6 weeks. 
  2. The engine must be operated on ultra-low sulfur diesel fuel (ULSD) of 15 ppm or less.
  3. The engine must be in proper operating condition, well maintained, and not consume lubricating oil at a rate greater than that specified by the engine manufacturer.
  4. The vehicle may not be equipped with an oil burning system and lube oil or other oils may not be mixed with the fuel.
  5. CDTi installs the back-pressure monitor and logger unit and the remote driver display on all vehicles equipped with a Purifilter Plus M.

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Verification Letters from EPA

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